Electrically-heated receptacle and hot plate



Sept. 16. 1924. 1,508,452

A. L. HARRINGTON ELEQTRICALLYHEATED RECEPTACLE AND HOT PLATE Filld arch 23 1923 .2 botti-Sheet 2 Heat: In'sulaUi/ng Makr'baL Patented Sept. 16, 1924.

UNITED STATES PATENT OFFICE.

ALFRED L. HARRINGTON, OF ROSSLYN FARMS, PENNSYLVANIA, ASSIGNOR TO PITTS- BURGH :PLATE GLASS COMPANY, A CORPORATION OF PENNSYLVANIA.

ELEGTRIGALLY-HEATED RECEPTACLE AND HO'I PLATE.

Application mea mmh 2s, ma. serial No. 627,081.

To all whom it may concern.'

Be it known that I, ALFRED L. HARRING- TON, a citizen ofthe United States, and a1 resident of Rosslyn Farms, in the county.v

of Allegheny and State of Pennsylvania, have made, a new and useful invention in Improvements in Electrically-Heated Receptacles and Hot Pla-tes, of which the following is a specification.-

The invention relates to electrically heated receptacles and hot plates and is particularly designed for use in the paint or varnish business, although capable of wide application and is not limited to use in connection with paint or varnish kettles or even to receptacles, being applicable as well to hot plates. The principal objects of the invention are to produce an improved construction giving a close control over temperatures; which promotes self mixing;

which provides for rapid cooling when thisr becomes necessary; and which leaves the bottom of the kettle unobstructed to permit proper stirring. Certain embodiments of the invention are illustrated in the accompanying drawings wherein:

'Figure 1 isl a vertical section through a varnish vkettle with the invention applied thereto. Fig. 2 is a partial plan view. Fig. 3 is a vertical section through a modi-fied construction. Fig. 4 is a plan view of a detail of the Fig. 3 construction. Fig. 5 is an enlarged section through the connection at the bottom of the F ig. 3 apparatus. And Fig. 6 is a vertical section through a hot plate construction with the invention applied thereto.

In its preferred form, the invention contemplates the heating of a kettle or receptacle by the application of a secondary current induced through the bottom of the kettle which is made of high resistance material. A primary exciting coil is located beneath this high resistancebottom with the second bottom below such coil and connections are provided at the center .of the two plates and at their peripheries, thus providing a closed secondary circuit. Thecurrent induced in the high resistance bottom flows between the center and periphery thereof heating the central portion more than the outer portion if `the bottom is made of uniform thickness, thus tending to promote a circulation of the liquid' in the kettle, an upward flow being produced at the center and a downward iow at the periphery. When the invention is applied to a hot plate, the principle of operation involved is the same except that it is preferable to increase the thickness of the high resistance plate from the edgeto the center so that the heatlng effect` upon the plate will be the same throughout rather than hotter at the center as 1s the case where the invention is applied to a kettle. The bottom of the high resistance plate is preferably covered with insulatingmaterial such as asbestos plaster, and means are provided for causing a circulation of lair through the space between the' bottom plates occupied by the primary coll 1n order to cool such coil. The same circulation means is also preferably employed for cooling the sides of the receptacle which are preferably made in the form of a double, wall with a space between through which the air is circulated when it is desired .to cool the contents of the kettle rapidly. v l

Referring to Figs. 1 and 2 which illustrate the invention as applied to a varnish kettle, the Vprincipal arts may be enumerated as follows: 1y is the supporting framework in the form of a heavy ring provided with the axles 2 carrying the wheels 3; 4 is the inner side. wall of the receptacle; 5 and 6 are sectionsof the outer side wall; 7 and 8 are clamping rings at the upper end of the side walls 9 and 10 are similar rings at the lower end thereof; 11 is the bottom wall of the kettle or receptacle of high resistance material such as nichrome; 12 is an insulating coatingy of asbestos plaster or similar material on the bottom of the plate 11; 13 is a ysecond bottomwall spaced below the wall 11; 14 is a supplemental side wall connectin'g the walls 11 and 13; 15 is an outlet pipe provided with a branch 16 leading laterally; 17 is a valve for the pipe carried by the stem 18 and operated from the lever 19 having the handle 20; 21 is aV primary exciting coil loca-ted between the walls 11 and 13 and encircling the outlet pipe 15; 22 is a motor driven blower having the connection 23 leading to the space between t-he two bottom plates 11 and 12 and the connection 24 leading to the space between the walls 4 and 5; and 25 is a valve for regulating or cuttin oif the supply of air flowing to the space between the walls 4 and 5. Thewalls 4, 5, 13 and 14 are all preferably made of sheet copper, While lthe outletv pipef15 and the surrounding sleeve 26"'are alsopieferriphery.y 'This Ais regarded Aas"desrable as'v ably of copper. The sleeve 26 acts as a spacer bet-Weenvthe Walls lland ,13, andNis pressed tightly up against the bottoni of the Wall 11 by means of the nut 27. The ilange 28 at the upper 'end ofethe pipe 15'- whieh opposes the flange of the sleeve 26 is preferably brazed to the platel 11'.y The lower end of the pipe 15 is provided With a sleeve 29 threaded thereto and c` end a suitable stufhngboXBO' lThe primary exciting coil 21 surrounds the 'pipe 15 and sleeve "'26 and is s lplpplied With currentV4 from a suitable' source, 'not4 shown.VVV This coil is preferablylcircular'rin" form withl van ironpcore, 'but be. l'made in .accordance with variousdesigns.` The pla-tell ogfhigh resistance material sprefer-ably f madef of yuniform "thickness from center to circumference so/'that When acur-` rent ilows therethrough between thelente and circumference, the centralV portionls the greater heat at the center tends to ifm'- prove :the 'circulation in th'efkettle, g,'ivi;iigv

a more vigorous flow upward through: the

center with a corresponding reverse flovv -at/ the outside.- lf it is desiredtof'heat the bot-4' toin uniformly, the plate 1-*1 maybe iliade` of gradually increasing thickness from ylits periphery to its center. The current @in duced by the primary coil 21 `flovvs through A i the secondary circuiti which comprises :the

pipe 15 and sleeve 26 at theycenter, tliielbotn4 tom 13, the supplemental-side Wall 114, landl` the high? resistance bottom Walll'flll.`

A is'. secured 4from theblower 22, which V41air may 7be applied Without ymaterially cooling the bottom'plate 11 'because of .theiusewof the insulating'material'12.

tloften becomes desirable contents of4 the kettle, particularly at th conclusion vof `the heating. operation, 32H61 this is facilitated by theuse ofthe double Walls to which leads the pipe 24 lfrom the blower 22. When it is desired to avoid cool ing the contents, the valve l25.is1'c1osed, and

under such conditions, the .double Wall ,of-

` the kettle preventsheat losses because `Ofi the insulating layer of air between such,V

Walls. 11i-order to permit ofthe circula-V tion :of air Ybetween the Walls, the outlet; perforations k81 are :provided -in Vthe lWall 5 opposite the pipe 24; The -supplemental.` wall 14;.i`s similarly providedwith 4a rrying at its lovverj no ideati uw.

feratien '32 t0 permit a liow of air from the space between the Walls 11 and 13 and so facilitate the cooling operation.

e A .pairof clamping-rin s .3 3 and 34 e130 provided at the lower en of the supple'-` mental wall 14, and these clamping rings gare connected-to the clamping rings 9 and 10 by means of the rods 35 spaced at intervals-around the periphery of the kettle. This construction, including the tWo bottom Walls 1l and 13 and the side Wall 14 provides base or foundation for the kettle of exceedingly rig-id Construction. r'u'gating'of the Wall 6 takes care of the diffeiincein contraction and expansion of the innerand outer lWalls ofthe kettle due .tothe different temperature conditions to which they are `exposed,thus relieving the strain Which would otherwise .be imposed upon ,the lrett'l'e-if` n ige. yand 5 illustratea for-naef construction `in which the'feature .of heating the bottom of the kettle by indue.- t-ioii isv omitted,such bottom .being heated bythe passage directly therethrough of; a

i current of electricity. 'The vconstructi011 `foll'oivs thatof Figs. V land 2 in that thee-L1rrent -iows between .the pelpheryiof kl'flll bcttomlwall :and its centerv sol that when a plate of uniform thickness is emp.lhjysfl-` fils a :bottom Wall, aegreater heating v,ei-liet is .se-f.

cured fat the central portion of the 'Pla-ts. jiist as in .the construction 4of Figs. ,l :and 2,

The cor- Y amused soy Referring to :the drawings, 36 is. the inner side 1Wallet .the kettle; 37 the QlltsrzSll Wall; 38 is the outer 'bQtOmWall Q 'the @levice; ,139 is a packing ci. asbsstos'er other insulating material; 4Q is. a lid :0f the 'dev-ice made up of the pai-ref spaced plates Vwith interposed .insulating materiali-4:1 is the tette-11i -fwall or @latest-therssptefile magie of .high .resistance .material sach es 11ielneeme; el is a .anular terminal ring; 43 :and le are ,t leads -by means of which Curran cause'l-toipass tllrOligli the plate el.

Asia caterl -Figt sithetsrmral plate 42 is of annular form so that 'cirrrent is supplied-fromme lead 43 tothe entire perinllsryn the llsh resist-alls Plaie l- The side of-the platel and .pressed tightly .in

contact therewith by ,means of the nut i8. Theleadv-l `is Secured to the .shank ,eain any desired way.

invention troia hotl plats, 'latins-construe '-F,g. .\6 illustatesfthe ,application of the.

tion thetopfplate 49 ofhighresistance me.

- its vbottom side, such as asbestos plaster.

Spaced beneath the plate 49 is a second plate 51 of copper, and between the two plates is the primary inducing coil 52. Perforated side walls 53 also of copper connect the plates at their peripheries and the parts are held together by means of the series of bolts 54 arranged at intervals around the circumference of the device. The plates 51 and 53 are made of relatively thick material as compared to the resistance plate 49 in order to carry the necessary current without overheating. A connection at the center of the two plates is provided in the form of the brass bolt 55 having its head seated in a recess in the plate 49 and its other end threaded and provided with the clamping nuts 56 and 57 lying above and below the plate 5l. Surrounding the bolt 55 is a spacing sleeve 58 of copper. The bolt and sleeve together with the three plates 49, 5l and 53 constitute the secondary circuit, the bolts 54 also being preferably made of metal of high conductivity so as to assist in carrying the secondary current.

What I claim is:

l. In combination, a heating plate of high resistance material and connections whereby a iiow of heating current is provided between the periphery of the plate and its central portion.

2. In combination, a receptacle having a wall for contacting with the contents of the receptacle of high resistance material, and connections whereby a heating current of electricity is caused to ow through such wall and heat it.

3. In combination, a receptacle having its bottom wall of high resistance material and connections whereby a heating current of electricity is caused to iow ythrough such wall and heat it.

4. In combination, a receptacle having a metal bottom adapted to be heated by the passage of electrical current therethrough, and connections whereby a heating current is passed therethrough from the center to the outer portion thereof.

5. In combination, a receptacle having a bottom of high resistance material bulging downwardly and connections whereby a flow of heating current is provided between the periphery of such bottom and its central portion.

6. In combination, a heating plate of high resistance material constituting a part of a secondary coil or circuit arranged so that the current passes between the'periphery of said plate and its central portion and heats it by its passage, and a primary exciting coil or circuit in operative relation to said secondary circuit.

7. In combination, a receptacle having a wall for contacting with the contents of the receptacle of high resistance material, a secondary circuit o coil of which said wall forms a part, and a primary exciting coil or circuit in operative relation to said secs ondary circuit.

8. In combination, a receptacle having its bottom wall of high resistance material, a secondary circuit or coil of which said wall forms a part, and a primary exciting coil or circuit in operative relation to said secondary circuit.

9. In combination, a receptacle having its bottom wall of high resistance material, a secondary circuit or coil of which said bottom wall forms a part arranged so that the current passes between the periphery of such wall and its central portion, and a primary exciting coil or circuit in operative relation to said secondary circuit.

l0. In combination, a receptacle having its bottom wall of high resistance material, a second bottom wall below said bottom wall, connections between the centers and peripheries of the two walls so that such walls with the connections constitute a closed circuit and a primary exciting coil in the space between said walls and surrounding the central connection between them.

l1. In combination, a receptacle having its bottom wall of high resistance material, a second bottom wall below said bottom wall, connections between the centers and peripheries of the two walls so that such walls with the connections constitute a closed circuit, heat insulating means on the lower side of the first bottom wall, and a primary exciting coil in the space between said walls and surrounding the connection between them.

l2. In combination, a receptacle having its bottom wall of high resistance material, a second bottom wall below said bottom wall, connections between the centers and peripheries of the two walls so that such walls with the connections constitute a closed circuit, means for causing a flow ot air through the space between the walls, and al primary exciting coil in such space adapted to induce a secondary heating current through said closed circuit.

13. In combination, a receptacle having its bottom wall of high resistance material, a second bottom wall below said bottom wall, an outlet pipe of conducting material leading through said walls at the center thereof, a side wall of conducting material between the peripheries of said walls, so that such walls with the side wall and pipe lOO eonstitute a', Closed .cireuit, :and yaf primary exciting coil in the space between the 'bot-, tom Walls and siuvroundng Seid outlet pipe.

14. In combination, .e receptacle Yhaving'. a doubleside Welll with an ai space in said wall and with an inlet to said airspacegand an outlet therefrom, and rmeans fonforoing air through said inlet.

16. 1n eoinioinetion, a, reoeptalewhaying e Adouble sidewzvall with al1-.air space therfk 1n, .and a bottom wall Aof highresietenoe meteiial and eonstitutinge part. of a 'Secondary' oiitouit, insulating maiteel outfile 'lower Sid@ of seid bottom well, other side and bottom walls below seid bottom wall also'v @Onettut- 111g a peet ezt seid secondary pireut, e.

mary exciting @Oil loeted 'beneath :said bot-1 tom Well, and motor A.driven means for VSLL-1 1- plying ei;-` over tlfl. ,P ly @il @1nd through en .space 1n the 'eide wall.

testimony Wliereo, l have hereunto subsoorlbed my bille-21st dey of Maron,

,enelntefifom 

